Conventionally, technologies of transmitting difference data to implement printing have been proposed as technologies of implementing rapid printing in a print system. For example, at the time of implementing printing from a host, a technology of checking whether print data are those transmitted onto a host in the past, preparing difference data if the data were transmitted in the past, transmitting difference data to a printing apparatus, retaining the entire print data in the host, and thereby realizing the time crunch until a print result is derived has been disclosed (for example, Japanese Patent Laid-Open No. H8-267867).
On the other hand, in document management technologies, a technology of correlating a history of updates with a document as update history information and making reference to that update history information, thereby restoring an electronic document before and after an update in the past is proposed (see, for example, Japanese Patent Laid-Open No. 2003-216601).
However, since the technology in Japanese Patent Laid-Open No. H8-267867 having been described above determines whether or not print data were stored onto a host computer and transmitted in the past, in the case where the same document undergoes print from another host computer, the entire print data will be retransmitted, giving rise to a problem that a time crunch of data transfer time at the time of printing cannot be realized. In addition, the technology in Japanese Patent Laid-Open No. 2003-216601 is a technology focusing on realization of reliable document assurance for data and on storage so as to enable restoration of electronic documents over a great number of generations, but has taken no print into consideration, thus giving rise to a problem that update information included in a document will never be put into practical use at the time of printing this document.